For many years spine fin tubing has been used in heat exchange structures for air conditioners. In such heat exchangers the spine fin ribbon is wrapped about the evaporator tubing in a very tight knit fashion; that is, the spine fin ribbon is wound so that adjacent passes of ribbon are in contact and the fingers or spines are very closely spaced. With such a construction the spines or fingers provide a very large total surface area for heat transfer. At the same time the spines or fingers are so closely spaced that the overall structure acts much like a cylinder during manufacture. One attribute of that construction is that the spines are mutually supportive and resist being depressed or folded over when the tube is handled. One reason that air conditioner heat exchangers can use spine fin tubing with closely packed, very thin spines is that during normal operation they are not subjected to a build up of frost (frozen condensation).
Despite the successful use of spine fin tubing in air conditioners for many years, such heat exchange structures have not been used in refrigerator evaporators. It has been the belief of many experienced practitioners that spine fin materials are not suitable for use in refrigerator evaporators. One basis for the belief was that the frost build up in a refrigerator evaporator quickly would render the spine fin ineffective as a heat transfer structure. In addition it was believed that the spine fin structure, as used in air conditioners, was too delicate to withstand the handling involved in manufacturing and installing refrigerator evaporators. On the other hand it was believed that, if the size of the spines were increased sufficiently to withstand the rigors of manufacturing, then the evaporator would not have sufficient heat exchange capacity to be effective with the stringent size limitations normally imposed upon such evaporators.
Accordingly, it is an object of this invention to provide an improved refrigerator with an evaporator incorporating a spine fin heat exchange structure.
It is another object of this invention to provide such an improved structure in which the spine fin ribbon is wrapped about the evaporator tubing in an open spiral.
It is yet another object of this invention to provide such an improved structure in which the distance between adjacent passes of ribbon and the width of the base of the ribbon are asymmetric.
Further objects and advantages of the present invention will be apparent from the following description and features of novelty which characterize the invention will be pointed out in the claims attached to and forming a part of this specification.